Wiring an outdoor switch....basic question

[saveasteading]

I have an outdoor floodlight. The cable is on the outside wall and there is a normal indoors switch inside the front door.

I want to add a switch inline on the outdoor wall, to make it easy to switch off the light there.

I find I have suitable external switches in my box of bits.

For wiring there is one connector in and one out.  So do I put live wires into them, and  join the neutrals inside the box with a connector ? One of these screw over the end ones, or a connector block?

Ditto with the earth I assume.

 

With indoor light switches there are connectors for every wire, (in and out , in basic terms) so I'm confused why external switches should be different.

[joth]

The difference is single vs double pole switch (SPST Vs DPST standard abbreviation).

If the inside is a double pole it's probably an isolator switch: if the outside unit had a fault (water ingress) it might trip an rcbo by leaking neutral to earth if only live is disconnected, so for total disconnect both live and neutral are disconnected in an isolator switch. 

 

Normally adding a second switch you want a double *throw* switch (SPDT) and fully connect the two switched poles 

 

This means either switch can turn on/off the switch at any time regardless of position of the other switch.

If you put a SPST inline (in series) as you describe it will act as a disconnector, so you can turn lights off from outdoors but then can't turn them back on from inside without going out and toggle the outdoor switch back to the on position again.

 

 

 

[ProDave]

Are you prepared to change the cable between the indoor switch and the outdoor switch?  If not you probably won't be able to achieve proper 2 way switching.  Do you know how many cores are in the cable to the light?

 

Post a picture of the wiring to the indoor light switch if you can and the cable where you want to add the outdoor switch.

[joth]

If you want proper 2-way switching without replacing the cable, wireless is probably the way to go

https://www.tlc-direct.co.uk/Main_Index/Quinetic/index.html

replace indoor switch with a "Quinetic Wireless Switch c/w Built In Receiver".

Add one (or more) "Quinetic Kinetic Wireless Switches" wherever you need them.

 

[saveasteading]

Thanks. And you even anticipate the reason for doing this.

There appears to be a fault in the underground cable as it fails in wet weather. It must be 30 years old and prob put in by ultra-amateurs / as cheap as possible. It used to work a 250W floodlight but is only about 30W now with a replaced light.

I suspect the underground cable is domestic, indoor, 3 core, so intend to replace it with armoured from the post that has the light, to the house wall. Here I will put the new switch. Perhaps good practice also dictates a junction box?

I could just join the existing cable but it has been in the sun and weather for decades. So I  then intend to take a 2.5mm domestic cable into the house and there make a new connection (it is in the attic so easy to access and adapt.) I would encase that outside cable in ducting.

Tracing the existing indoor cable back to the indoor switch is likely to be very convoluted and messy. It  is a 3 gang switch at the front door, operating the lobby, an adjacent outdoor wall light and the distant light which is the issue. Just one of these 

[ProDave]

So you will want a 3 core 1mm Steel wire armoured cable from the house switch to the outside switch which will need to be a waterproof 1 gang 2 way switch.  These are usually in a back box with knock outs for the SWA cable gland.  Then from the switch 2 the light you only need 2 core but might as well use the same 3 core SWA to save buying 2 different lots.  Likely you will need a junction box by the light as few outside lights can directly take SWA glands.

[saveasteading]

Ok, so i put in swa with a junction box both ends.

Are you saying that i should also use swa from there into the house?

I'm happy (prefer) to keep the switching simple, so either switch works independently and both have to be on for it to work.

 

Being of simple mind I like to connect 3 cores in and 3 cores out (or 2, and link the earths) but will take instruction if there is a better way..

 

What is such a switch called? Double pole double throw?

 

 

[ProDave]

The bit inside the house does not need to be SWA.  But you WILL need 3 core plus earth from the light switch to the junction box where it connects to the SWA for the remainder of it's journey.

 

Ideally could you unscrew that switch and post some pictures of the wiring inside?  What I have describes is the simplest wiring possible but it may be this house is wired differently so it could be more complicated.

 

The inside switch almost certainly will be suitable, it would be very unusual to find a 3 gang switch that is not 2 way.  (3 gang means 3 switches on the one plate, 2 gang means it is a changeover switch with 3 contacts and not a simple on off switch with just 2 contacts)

 

There is no single way to wire light switching so lets start with finding out from those pictures how this is connected.

[saveasteading]

1 hour ago, ProDave said:

bit inside the house does not need to be SWA

Pictures show the existing cable up the wall. Should that be swa into the house or will normal cable in a duct suffice?

 

I will take the internal switch face off ...but isn't it simply going to be 3 cores heading off into the attic which are either on or off?

 

I will ask annoying questions later about gangs, switches and poles... it seems unnecessarily confusing.

Eg 3 gangs means 3 switches.  But 2 gangs means... not 2 switches but what you said

[ProDave]

The cable up the wall needs to be in trunking, conduit or why not just continue the SWA up into the loft and just have one junction box in the loft.

 

Yes the terminology is very confusing estpecially as "gang" has 2 different uses for 2 different things.

 

So Gang.  You can have 1 gang and 2 gang back boxes.  1 gang is square for a light switch or single socket, 2 gang is rectangular for a double socket or 4 way light switch.

 

You can have 1 2 3 or 4 gang light switches meaning the number of switches, where a 1,2 and 3 gang light switch fit in a 1 gang back box and a 4 gang light switch fits in a 2 gang back box.

 

Clear?

 

Switches, a simple on off switch is often referred to as 1 way.  It can turn a single light on and off from one place and has 2 terminals.  2 changeover switch has 3 terminals and is often referred to as 2 way.  It can be used just like a 1 way for a single light, or a pair of them can be used for 2 way switching.

 

Why anyone makes or anyone bithers to buy a 1 way switch beats me, a 2 way does everything and only costs a few pence more.

 

Then there is the intermediate light switch that confuses most people even more.

[saveasteading]

Here is the existing treble switch. Very congested, so I hope you can "read" it.

 

To complicate it, the left hand switch is 2 way. AND in turning off fuses i find that the right hand switch, the one that does the floodlight in question  is on a different circuit to the other 2 switches.

 

 

And yet I only see 2 cables.... over to you Mr Electrician.

[ProDave]

The left hand switch is definitely wired for 2 way, Red, yellow blue of one cable. That may well be on a different circuit.

 

The middle and right switch are on the same circuit and connected to the second cable.  Red is live feed looped to middle and right switches, blue is switched output from middle switch, yellow is switched output from right switch.

 

The complexity of your alteration has just gone up somewhat.  There are no junctions at the switch so it is either wired "loop at light" or quite likely spider fashion where everything goes to one great big junction box often in an unknown location.

 

Apart from locating that junction box, your biggest issue is no spare cores in the existing cables to use for the 2 way switching of the outside light.

 

At this point I suggest you find an electrician, this might be beyond remote diagnosis on a forum.

 

Somehow you are going to have to get an extra cable to that switch and it looks to be plastered brick or block so that means chasing a new cable into the wall and the re plastering and decorating afterwards.  If you choose to proceed I would install a new cable and wire the entire outside light as a complete new circuit.

 

 

[saveasteading]

OK thanks. Understood.

But if I have a cable that clearly works, including the switch, can't I simply find a nice condition part of it in the attic and join a new cable to it?

I appreciate it's not perfect or professional,  but will be much better than what is here now, for the interim. And circumstances do not permit pulling down walls and ceilings at present.

 

I have spoken to a couple of really sound electricians and they want to spend thousands on exploratories, tests and rewiring. And of course I'll still end up putting the swa in.

 

My interim switch idea was partly so that I can do this diy bit, while ensuring it is ready for a proper job when funds and circumstances allow.

ie new swa cable 25m fixed to post and wall. Switch. Short (7m) cable from switch into house,  joining to the existing in a new junction box indoors. 

That will be much easier to handle too than 32m swa.

 

Then later the link from there can be surveyed and completed.

 

Which doesn't resolve my original question  ..what is the outdoor switch called?

3 wires in, 3 wires out I assumed.

 

Or it is live in and out of the switch, and join the neutral ends within the box?

 

I've looked at screwfix and other specs, and instructions within the switches I have already,  and indeed they throw around the terms switch/gang/ way/ pole as if they are interchangeable.

 

@joth thanks to you too. The circuit you show doesn’t apply as my existing is a simple switch. But I think you havd provided the beginnings of an inkling of how L1 to Com works and doesn't go bang.

 

[Mr Punter]

3 minutes ago, saveasteading said:

And of course I'll still end up putting the swa in.

 

I have used Hi Tuff cable for external wiring in the past.  It is more flexible and easier to fit and terminate than SWA.

[saveasteading]

1 hour ago, Mr Punter said:

Hi Tuff cable

Another thing learned today . I hadn't heard of this. 

From a quick read up, this would be ideal for the face of the wall, but not underground.

[ProDave]

Without proper wiring alterations, proper 2 way switching won't work.

 

What you could do without tearing your house apart, is put an outside switch in series with the inside switch.  So IF the inside switch is on, then you could turn the outside light on and off from the outside switch.  But if the inside switch is off, then the outside switch would do nothing.

 

If that compromise was okay then yes you could continue using the cable going through the house and down the wall.

[-rick-]

12 hours ago, joth said:

If you want proper 2-way switching without replacing the cable, wireless is probably the way to go

https://www.tlc-direct.co.uk/Main_Index/Quinetic/index.html

replace indoor switch with a "Quinetic Wireless Switch c/w Built In Receiver".

Add one (or more) "Quinetic Kinetic Wireless Switches" wherever you need them.

 

 

Wouldn't this be a better solution in this case @ProDave? Saves doing anything inside the wall or serial switching. Can still replace the external cable if needed but just use a wireless external switch (they sell IP67 versions).

[saveasteading]

9 hours ago, ProDave said:

continue using the cable going through the house

That was the plan. I should have explained better at the start... in series.

@-rick- the issue is with thd power cable being faulty. The fuse trips afteg heavy rain.

 

I'm still none the wiser about what outside switch to buy.  

 

This is top of the search from screwfix. Same words as @ProDave used earlier.

British General IP66 20A 1-Gang 2-Way Weatherproof Outdoor Switch with Neon (54649)

 

Will I need to tie the neutrals together inside it?  What is one if those wind- on plastic caps called?

 

Presumably this switch is OK for swa.

 

One more question. 1.5mm2 swa costs £43 for 25m .    2.5mm2 costs £53. Any reason not to invest that £10 in case of future upgrades?

[Nickfromwales]

9 hours ago, -rick- said:

 

Wouldn't this be a better solution in this case @ProDave? Saves doing anything inside the wall or serial switching. Can still replace the external cable if needed but just use a wireless external switch (they sell IP67 versions).

1000%. 
 

@saveasteading, just renew the cable so the light has a permanent live feed and go to Quinetic.
 

Just so quick and simple, and you can add switches in seconds anywhere you want them. They are really effective, but the question would be what the distance from the light to the indoor switch is, as you’ve got options to just put an IP project box next to the floodlight and the switches talk to that there, vs trying to get a bulky Qtc switch into the box box you have in the wall.
 

They’re a bloody tight squeeze, did this in my daughters bedroom and works a treat; switch by the door, and desk, and bedside 👍. All done in an hour start to finish. 

[ProDave]

Yes the Quinetic is the way to go,

 

So I would replace the 3G existing switch with a 2G, linking the L out to outside light to live so that cable is now always on.  Fit the outside Quinetic switch in line with that existing outside cable, and then find a location for the inside Quinetic which can be anywhere convenient.

[dpmiller]

are you absolutely sure the fault is in the cable rather than the light?

 

the windy-on plastic things are called "wire nuts" and we're not in the US so you'd be better off thinking about Wagos...

[Nickfromwales]

8 minutes ago, ProDave said:

Yes the Quinetic is the way to go,

 

So I would replace the 3G existing switch with a 2G, linking the L out to outside light to live so that cable is now always on.  Fit the outside Quinetic switch in line with that existing outside cable, and then find a location for the inside Quinetic which can be anywhere convenient.

Didn’t know this until a previous job, but you can buy another receiver and put it into ‘slave’ mode so it acts as a repeater. Just needs AC power 24/7 but it can be fed from any circuit anywhere, as it just needs to be ‘alive’ to work the lights.

 

Can't recall what they refer to it as, but the tech support for Qtc is pretty good.

[ProDave]

The wind on caps were called Screwits here and were made of porcelain.  I used to still find some in use on old houses.  But don't even think of using them today. 

[saveasteading]

20 minutes ago, dpmiller said:

windy-on plastic things are called "wire nuts" 

I found one in my box of bits. Upmarket of insulating tape.   I've got some wagos too.

20 minutes ago, dpmiller said:

are you absolutely sure the fault is in the cable rather than the light?

Yes. The light is currently disconnected at the adjacent junction box. I can't remember why!

Switch in the house was left on in error. Fuse tripped during a huge downpour. Not tripping now the ground had drained.

But nothing is ever certain. Whatever, it should be swa not the present cable.

 

It is 23m to the house as photo, but 35m to the front door.

Edited yesterday at 08:04 by saveasteading

[ProDave]

Was it really a "fuse" that went when it got wet?  Or an RCD?